1. Field of the Invention
The present invention relates generally to printed circuit wiring boards, and, more particularly, to an adjustable clamp lock for edge-locking such boards within individual mounting recesses.
2. Description of Related Art
Printed circuit boards generally comprise a rectangular base made of an electrically insulative material onto which circuit components are surface mounted and interconnection between the components is established by deposited leads of a conductive material laid down in a predetermined pattern. Interconnection between boards or between a board and other equipment is typically achieved via deposited electrodes arranged along a board edge. In order to protect the components and interconnection leads, the boards are typically mounted in an edge supported manner.
Known systems for securing printed wiring boards are of three main categories. First of all, so-called "complete perimeter systems" include apparatus which clampingly engage the full board periphery. Other systems have isolated pads which coact to secure the board. Finally, two-edge mounting systems are especially desirable when high volume efficiency, parallel face mounting and ease of assembly are required factors.
However, available clamping devices for two-edge mounting of boards present most difficult problems for a printed circuit board structural support chassis. For example, they frequently utilize a single screw to actuate the device, and the resultant configuration produces high loads in a relatively small area which can lead to structural failure. Also, these known devices do not provide more than minimal vibrational damping, are relatively expensive to manufacture, and do not provide a desired minimum preload after material stress relaxation and creep have set in. Still further, available two-edge mounting devices are not completely satisfactory where the boards or supporting structures must survive in increasingly hostile environments after long term storage, e.g., control system for a missile.
Accordingly, it would be desirable to have improved two-edge mounting systems at least to the extent of eliminating deficiencies of presently known two-edge mounting systems.